Fallacies of Risk

In addition to traditional fallacies such as ad hominem, discussions of risk contain logical and argumentative fallacies that are specific to the subject-matter. Ten such fallacies are identified, that can commonly be found in public debates on risk. They are named as follows: the sheer size fallacy, the converse sheer size fallacy, the fallacy of naturalness, the ostrich's fallacy, the proof-seeking fallacy, the delay fallacy, the technocratic fallacy, the consensus fallacy, the fallacy of pricing, and the infallability fallacy. Ever since Aristotle, fallacies have had a central role in the study and teaching of logical thinking and sound reasoning. (Walton 1987) It is not difficult to find examples of traditional fallacies such as ad hominem in any major modern discussion of a controversial issue. Discussions on risk are no exception. In addition, the subject-matter of risk (like many others) seems to invite to fallacies of a more specific kind. The purpose of this short essay is to discuss ten logical and argumentative fallacies that can be found in public debates on risk. Some of these are not as rare in the scholarly and scientific literature as one might have hoped. 1. The sheer size fallacy X is accepted. Y is a smaller risk than X. Y should be accepted. This is one of the commonest fallacies in the lore of risk. It is not often found in recent scientific writings, but is still often heard from advocates of various risk-associated technologies: “You will have to accept this chemical exposure since the risk it gives rise to is smaller than the risk of being struck by lightning.” Or: “You must accept this